I’m using Notepad++ with a few plugins at the moment, but my editor of choice is actually Kate (again with a few plugins), which is part of the KDE project.
My main issue with Notepad++ is that you seem to only be able to open one window at a time, which is a real pain when you want to work in multiple FTP repositories at once. It’s parenthesis highlighting doesn’t get replicated in the code minimap either which somewhat defeats the point of having a minimap at all in my view.
Kate is tonnes better, basically.